Feature Articles

Why Multi-Core and Power-Optimized Platforms

Why Multi-Core

Rattner's keynote continued with a sort of 'debunking the myth' presentation on why multi-core is the future of computing. Why push for multi-core now? Again energy became the key focus and not performance per se. Rattner gave a simple explanation that the power required to ramp up a single core processor does not scale well with the performance gains. Yes it can be done, but you could possibly be increasing power by 70% for mere 13% gains. Instead, Intel turned towards downclocking the processor, reducing power by 50% and found out that the reduced frequency would only relate to a 13% performance loss. However, because the power consumption is now so low, slapping on a second core would basically only bring up the power levels to where it was originally, but featuring two execution cores for a much better performance gain.

The illustration given was a very simple example using static and unconfirmable figures, but we find it effective to get the message across on how multi-core technology is helping to increase performance while keeping the power envelop low or in check. The same concept is then applicable to quad core and beyond.

Power-Optimized Platforms

With the Core microarchitecture and multi-core technologies, Intel has reached a milestone in delivering energy efficiency on the microprocessor level and thus they begin their focus on the next level of power optimization and that is to look at power-optimized platforms. Rattner continued his keynote speech detailing how platform power consumption will now be Intel's next challenge, effectively trying to squeeze more energy efficiency from the platform level. "Processor power is only a third of total platform power, while the rest of the platform is dominating energy consumption", Rattner stated. Because of this, Intel is looking into ways to further increase idle mode efficiency and one of the methods in research now is the Display Self-Refresh.

Rattner then showed a prototype design for Ultra-Mobile PCs called the Silverton platform, which has experimental platform power saving features built in. On idle, the platform runs at about 6.5W and with extended I/O mode enabled, the platform power consumption has been reduced to 3.5W, but loses none of its responsiveness. Power was then cut off to the motherboard, so that they could demonstrate the Display Self-Refresh mode, which kept the monitor up, but now energy consumption has dropped to 1W. We'd like to remind you that these are basically proof-of-concept demonstrations by Intel into their efforts in developing Power-Optimized Platforms, so don't be expecting the upcoming Santa Rosa, Bridge Creek or Averill platforms to run on 1W idle.